First: As we have stated, the (royal authority), by its
very nature, must claim all glory for itself. As long as glory was the
common (property) of the group, and all members of the group made an
identical effort (to obtain glory), their aspirations to gain the upper
hand over others and to defend their own possessions were expressed in
exemplary unruliness and lack of restraint. They all aimed at fame.
Therefore, they considered death encountered in pursuit of glory, sweet,
and they preferred annihilation to the loss of (glory). Now, however,
when one of them claims all glory for himself, he treats the others
severely and holds them in check. Further, he excludes them from
possessing property and appropriates it for himself. People, thus,
become too lazy to care for fame. They become dispirited and come to
love humbleness and servitude.

The next generation (of members of the dynasty) grows up
in this (condition). They consider their allowances the government's
payment to them for military service and support. No other thought
occurs to them. (But) a person would rarely hire himself out to
sacrifice his life. This (situation) debilitates the dynasty and
undermines its strength. Its group feeling decays because the people who
represent the group feeling have lost their energy. As a result, the
dynasty progresses toward weakness and senility.

Second: As we have said before, royal authority by its
very nature requires luxury. People get accustomed to a great number of
things. Their expenses are higher than their allowances and their income
is not sufficient to pay for their expenditures. Those who are poor
perish. Spendthrifts squander their income on luxuries. This (condition)
becomes aggravated in the later generations. Eventually, all their
income cannot pay for the luxuries and other things they have become
used to. They grow needy. When their rulers urge them to defray the
costs of raids and wars, they cannot get around it (but they have no
money). Therefore, (the rulers) impose penalties on the (people) and
deprive many of them of their property, either by appropriating it for
themselves or by handing it over to their own children and supporters in
the dynasty. In that way, they make the people too weak (financially) to
keep their own affairs going, and their weakness (then reacts upon the
ruler and) weakens him.

Also, when luxury increases in a dynasty and people's
income becomes insufficient for their needs and expenses, the ruler,
that is, the government, must increase their allowances in order to tide
them over and remedy their unsound condition. The amount of tax revenue,
however, is a fixed one. It neither increases nor decreases. When it is
increased by new customs duties, the amount to be collected as a result
of the increase has fixed limits (and cannot be increased again). And
when the tax revenues must go to pay for recently increased allowances
that had to be increased for everybody in view of new luxuries and great
expenditures, the militia decreases in number from what it had been
before the increase in allowances.67

Luxury, meanwhile, is still on the increase. As a result,
allowances become larger, and the militia decreases in number. This
happens a third and a fourth time. Eventually, the army is reduced to
the smallest possible size. The result is that the military defense of
the dynasty is weakened and the power of the dynasty declines.
Neighboring dynasties, or groups and tribes under the control of the
dynasty itself, become bold and attack it, and God permits it to suffer
the destruction that He has destined for (all) His creatures.

Furthermore, luxury corrupts the character. (Through
luxury,) the soul acquires diverse kinds of evil and sophisticated
customs, as will be mentioned in the section on sedentary culture.68
People lose the good qualities that were a sign and indication of (their
qualification for) royal authority.69
They adopt the contrary bad qualities. This points toward retrogression
and ruin, according to the way God has (planned it) for His creatures in
this connection. The dynasty shows symptoms of dissolution and
disintegration. It becomes affected by the chronic diseases of senility
and finally dies.

Third: As we have mentioned,70
royal authority, by its very nature, requires tranquility (and rest).
When people become accustomed to tranquility and rest and adopt them as
character traits, they become part of their nature. This is the case
with all the things to which one grows used and accustomed.

The new generations grow up in comfort and the ease of
luxury and tranquility. The trait of savagery (which former generations
had possessed) undergoes transformation. They forget the customs of
desert life that enabled them to achieve royal authority, such as great
energy, the habit of rapacity, and the ability to travel in the
wilderness and find one's way in waste regions. No difference remains
between them and ordinary city dwellers, except for their (fighting)
skill 71and emblems.
Their military defense weakens, their energy is lost, and their strength
is undermined. The evil effects of this situation on the dynasty show
themselves in the form of senility.

People, meanwhile, continue to adopt ever newer forms of
luxury and sedentary culture and of quiet, tranquility, and softness in
all their conditions, and to sink ever deeper into them. They thus
become estranged from desert life and desert toughness. Gradually, they
lose more and more of (the old virtues). They forget the quality of
bravery that was their protection and defense. Eventually, they come to
depend upon some other militia, if they have one.

An example of this is the nations whose history is
available in the books you have. What I have said will be found to be
correct and admitting of no doubt.

In a dynasty affected by senility as the result of luxury
and rest, it sometimes happens that the ruler chooses helpers and
partisans from groups not related to (the ruling dynasty but) used to
toughness. He uses (these people) as an army which will be better able
to suffer the hardships of wars, hunger, and privation. This could prove
a cure for the senility of the dynasty when it comes, (but only) until
God permits His command regarding (the dynasty) to be executed.

This is what happened to the Turkish dynasty in the East.
Most members of its army were Turkish clients. The (Turkish) rulers then
chose horsemen and soldiers from among the white slaves (Mamelukes) who
were brought to them. They were more eager to fight and better able to
suffer privations than the children of the earlier white slaves (Mamelukes)
who had grown up in easy circumstances as a ruling class in the shadow
of the government.

The same was the case with the Almohad(Hafsid)
dynasty in Ifriqiyah. Their rulers often selected their armies from the
Zanatah and the Arabs. They used many of them, and disregarded their own
people who had become used to luxury. Thus, the dynasty obtained
another, new life, unaffected by senility.